As electronic devices are scaled down, rectifier elements are also expected to be scaled down. For example, a resistive random access memory is provided with a memory cell having a variable resistance layer at the intersection of a word line and a bit line. Application of a voltage to the variable resistance layer causes a change in the resistance of the variable resistance layer and realizes a memory function. If the memory cell does not have a rectification property, a leakage current flowing through a non-selected memory cell can cause a malfunction. The memory cell is thus preferably provided with a rectifier element.
The resistive random access memory is required to have a scaled-down memory cell in order to increase the storage capacity. For this reason, scaling-down is also required for the rectifier element provided in the memory cell. As for a pn diode utilizing a pn junction of a semiconductor, it is difficult to reduce the size to 10 nm or smaller, for example, because a reduction in size increases a tunneling current.